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SAN FRANCISCO (KCBS/AP) – People tend to wake up in a good mood — and they are happiest on weekends.

That trend is confirmed by a study of Twitter activity. Researchers looked at English-language tweets from 2.4 million in 84 countries. They used a computer program that searched for words indicating positive mood — happy, enthusiastic, brilliant — or negative mood — sad, anxious, fear.

KCBS’ Larry Magid Comments:

Tech Report: Twitter Acts As Modern Day Mood Ring

They found that unless you’re a night owl, a positive attitude peaks early in the morning and again near midnight. It starts to dip in mid-morning before rising again in the evening.

But it’s not just work-related stress that causes that dip. A researcher points out that the same midday dip occurs on the weekend. He says the pattern is probably due to the effects of sleep and our 24-hour biological clock.

The study appears in the journal Science.

“Whether this is scientific or not, I’m not quite sure because they’re not doing the kind of random sampling that a pollster would do,” said KCBS Technology Analyst Larry Magid. “But they are mining a lot of data, and when you consider that they looked at 2.4 million tweets, that’s probably a pretty accurate portrayal of the nation.”

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